These days, home security systems are coming into wide use; in the home security system, burdens such as new equipment investment and installation work, for example the need to install a human sensor using infrared light or the like, are imposed. Hence, technologies to create a home security system simply are being developed.
For example, Patent Literature 1 below proposes a technology in which electrical devices having a function of wireless communication are used, and an electrical device having a function of wireless communication and existing in a house is registered in advance; and in a case where a home security system is in a warning standby mode and a response signal concerning wireless communication is emitted from an unregistered electrical device, the home security system is transitioned to a warning mode.